1. Field of the Invention
The invention relates to a load driving device, a vehicle equipped with the load driving device, and a method of controlling the load driving device, and more particularly, to preventing overcurrent from occurring in a load driving device that includes a plurality of power storage devices connected in parallel, to one another.
2. Description of Related Art
Japanese Patent Application Publication No. 2002-84666 (JP-A-2002-84666) describes a battery system for an electric vehicle. In the battery system, a battery includes a plurality of unit battery cells connected in series to one another. Each of the plurality of the unit battery cells is provided with a discharge circuit. When a motor that propels the electric vehicle is stopped, a microcomputer is regularly activated to calculate the SOC of each of the unit battery cells. Then, when a difference in SOC between the unit battery cells is equal to or larger than a threshold value, the discharge circuit is driven through a discharge control signal from the microcomputer. Thus, the capacity of each of the unit battery cells is corrected.
According to the battery system, the dispersion of the self-discharge amount among the plurality of the unit battery cells may be easily corrected. Accordingly, it is supposed that the capacity of the battery can be sufficiently exploited, and that the reliability of the battery system can be enhanced (see Japanese Patent Application Publication No. 2002-84666 (JP-A-2002-84666)).
In electrically propelled vehicles such as hybrid vehicles, electric vehicles, for example, various attempts to increase the storage capacity of the power storage portion to improve drivability such as acceleration performance, sustainable traveling distance, or the like. A configuration in which a plurality of power storage devices are connected in parallel has been studied as a means of increasing the capacity of the power storage portion. In such a system, components (e.g., fuses) of the plurality of the power storage devices and components (a system main relay, a power element of a boost, device connected to the power storage portion, and the like) supplied with the resultant current from the respective power storage devices need to be appropriately protected from overcurrent, while ensuring the motive energy performance of the vehicle by sufficiently exploiting the capacities of the respective power storage devices. In the aforementioned Japanese Patent Application Publication No. 2002-84666 (JP-A-2002-84666), this problem and its solution are not taken into consideration.